Marine scientist Ellen Prager clearly “gets it” about effective science communication. That was obvious just from the title of her presentation on science communication at the AGU meeting last week: Sex, Drugs & Sea Slime (borrowed from her book title).

To demonstrate the importance of audience engagement, Prager flashed on the screen photos of bizarre larval forms of common sea animals, and asked the audience to guess what each would grow into.

Soon the audience was shouting answers (“a pig?”) and laughing; she had us. (Try guessing the critter below, then see the answer at the end of this post.*)

Prager’s little guessing game not only got everybody involved. It showed the power of arresting images, and demonstrated a another important principle of effective communication: create suspense.

Whenever we run into a knowledge gap — something we don’t know — we get at least a bit curious. It’s like an itch we have to scratch. The same cognitive process makes us want to see “what’s around the corner” and eagerly turn the page to find out “what happens next” in a good novel.

In my favorite messaging handbook, Made to Stick, Chip & Dan Heath discuss in detail the psychology of “knowledge gaps,” pioneered by behavioral economist George Lowenstein. A knowledge gap is one way to fulfill the Hollywood screenwriter’s maxim described by marine-biologist-turned-filmmaker Randy Olson’s (Don’t be Such a Scientist): “arouse and fulfill.” First, make the listener curious or want something, then give it to them.

The nice thing about building suspense is that you don’t need to be a novelist or script-writer to do it. Simply animating your PowerPoint graph, withholding the key data at first, opens a gap, sparks curiosity, builds suspense and — if your final data are sufficiently dramatic and unexpected — sometimes elicits a startled gasp.

You can hear those audience gasps during a lecture by University of Toledo chemistry Prof. Andy Jorgenson, who has developed suspenseful graphs into a fine art. In”Yes, Climate Change is Real. So What Can We Do About it?” fast forward to 14:50. First Jorgenson shows earth’s past CO2 levels, then asks his students “what level do you think might be worrisome?” When he finally unveils the parabolic 2oth century rise — the “handle” on the “hockey stick” — you can hear a murmur pass through the class. He does it again at 21:00 with global temperature, at 26:00 with global emissions, and at 34:00 with projected CO2 levels.

Jorgenson’s slide show may not be as gripping as a page-turning novel or a Hollywood blockbuster, but he creates a bit of suspense by posing questions, withholding answers, and getting his audience engaged in guessing games.

We can’t leave this topic without pointing out that the title of Prager’s book itself demonstrates yet another major principle of effective communication, detailed in Randy Olson‘s book. It’s a principle that most scientists, who tend to “lead with their head,” routinely violate. (Can you guess?)

If you really want to grab and keep an audience’s attention, and make your message stick, you have to appeal not only to the mind, but to lower parts of the body as well: the heart (emotions), the gut (laughter and instinctive reactions), and, lower down, “those naughty sex organs.”

So which region did Prager reach for in her book title? While you are at it, consider the cover photo of the octopus, and the overleaf photo of the author (right). Everything appeals to the senses and sensuality; nothing suggests “this is going to be heady and boring.”

I’ll venture another guess: In two days, if you remember anything from this post, it will be either a) the title of Prager’s book or b) one of the photos. Just to be sure, here’s one last photo. Olson uses a beefy public figure to illustrate the “four organs of mass communication.”